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by pcwalton 3745 days ago
> Also Swift's compiled code does not get near the same performance as Go's compiled code. Even when you unsafely compile Swift's code, it doesn't get near.

Do you have a source for this?

Swift had the long term in mind anyway. The effort to create SIL, along with the industrial-strength LLVM pipeline, has led to a rock-solid foundation. It's hard to compete with a backend that has 4 separate IRs, each with its own suite of optimization passes, including hundreds of algebraic simplifications, a highly tuned register allocator, an instruction scheduling pipeline, and an autovectorizer, just to scratch the surface. The stage is set for an excellent compiler architecture, even if they're not there today.
1 comments
devsquid 3745 days ago
Heres from a quick Google

http://benchmarksgame.alioth.debian.org/u64q/compare.php?lan...

You can see like most Swift benchmarks, its compiling with the -Ounchecked flag and using C.

-edit- I have no doubts of LLVM's capabilities. It just seems like Swift is probably already taking advantage of its optimizations.

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alblue 3744 days ago
One surprising performance issue with Swift was identified (and fixed) by IBM recently:

https://github.com/apple/swift/commit/259d57bbe7784955108caa...

The problem was that the print operations was being done character-by-character and it resulted in the printing being a significant overhead in the execution of the tests themselves. With this change they saw a speed up of many times simply because it was using buffered output.

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pcwalton 3744 days ago
> It just seems like Swift is probably already taking advantage of its optimizations.

The Go compiler performs nowhere near the level of optimization that LLVM does; LLVM is years and years ahead. However, LLVM is fundamentally a C compiler and so there can be impedance mismatch between Swift and LLVM. Hence SIL. This is what you're seeing, and once the gap is closed then Swift will reap the benefits of the hundreds of optimizations in LLVM.

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igouy 3744 days ago
You did say "Even when you unsafely compile Swift's code, it doesn't get near." ;-)

fannkuch-redux looks near, mandelbrot looks near, n-body…

Swift is new to Linux; there's a new compiler snapshot about every 10 days. Swift has only been available on the benchmarks game 3 months for people to contribute programs. Early days :-)

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